2. amps-preamps
  3. 1011704690

Tubed Amp Troubleshooting

Need a bit of help/advice from the tube guru's. The mid/bass on my right channel started to drop out upon warm up this weekend. System will sound OK for the first hour or so after amps are turned on, but the mids/bass will drop out suddenly. At first I though it wast the mid/bass driver on the speaker, so I switched the speakers. However, the problem is still there with the speaker that worked fine on the left channel before. Last night I put in a new 6AN8 driver tube, but the problem cropped up again. Next step is to put in a new quad of power tubes and see if this fixes the problem. I will try that tonight, but wanted to see if anyone had other troubleshooting ideas. Thanks!
128x128alexc

Showing 3 responses by alexc

alexc's avatar
alexc OP
265 posts
 
First thing I tried...but I'll try it again.
alexc's avatar
alexc OP
265 posts
 
Well, it seems like it was the power tubes. Anew quad of KT 88's seems to have taken care of it. For further referecne, the problem was present with both analog and digital sources (each going into different input of the preamp via different cables). Switching the left and right channels at the preamp output showed the problem followed the amp (and associated cabling) on the right. So, this told me it wasn't a source component or preamp issue. A cable short is not totally ruled out yet, and will be the next thing to check if the problem comes back, but for now it seems to be ok.
alexc's avatar
alexc OP
265 posts
 
Well, so far I've had no more problems (after putting in new power tubes). The amps are Aronov 9100, each with 4 KT 88 tubes. The old tubes were about 18 months old, but had quie a few hours on them since I've burned in 2 pairs of speaker cables and three sets of power cords with them since I bought them
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